Reference may be made to the following U.S. Pat. Nos. 3,509,339; 3,509,341; 3,578,960; 3,717,762; 3,720,469; and 3,578,980.
Several of the aforementioned patents illustrate diagnostic apparatus for analyzing a plurality of radioactive emitting samples and providing a sample count for a discrete sample. Generally, such systems detect the number of radioactive particles being emitted from each sample by utilizing a light emitting crystal, such as sodium iodide. The light pulses are converted by a photomultiplier tube into electrical pulse signals so that the sample count for each sample can be obtained. Whereas such systems are suitable for obtaining the sample count when only one sample is to be analyzed, a particular problem exists in the total length of time required to obtain a sample count for all samples where a plurality of samples are to be analyzed. This is due to the fact that the type of radioactive material normally utilized in such systems decays very slowly and the emitted gamma particles must be detected over a long time interval in order to obtain the degree of precision required in diagnostic instruments. It for example, approximately 10,000 counts are required to obtain a 1% precision, this would normally require approximately one minute of counting time per sample. Where there are a large number of samples to be analyzed, the total counting time becomes very significant, and it is highly desirable to obtain an overall reduction in the counting time without sacrificing the precision required of diagnostic instruments.